[PATCH v7 2/4] firmware: raspberrypi: Introduce vl805 init routine

Nicolas Saenz Julienne
2020-04-29T16:48:19Z

The Raspberry Pi 4 gets its USB functionality from VL805, a PCIe chip
that implements xHCI. After a PCI reset, VL805's firmware may either be
loaded directly from an EEPROM or, if not present, by the SoC's
co-processor, VideoCore. RPi4's VideoCore OS contains both the non public
firmware load logic and the VL805 firmware blob. The function this patch
introduces triggers the aforementioned process.

Signed-off-by: Nicolas Saenz Julienne <nsaenzjulienne@suse.de>

---

Change since v6:
- Add test to avoid loading the firmware when not needed
- Since we have it around, print VL805's firmware version, it'll make
debugging easier in the future
- Correct typos
- Add a clearer view of HW topology in patch description

Changes since v4:
- Inline function definition when RASPBERRYPI_FIRMWARE is not defined

Changes since v1:
- Move include into .c file and add forward declaration to .h

drivers/firmware/raspberrypi.c | 52 ++++++++++++++++++++++
include/soc/bcm2835/raspberrypi-firmware.h | 7 +++
2 files changed, 59 insertions(+)

diff --git a/drivers/firmware/raspberrypi.c b/drivers/firmware/raspberrypi.c
index da26a584dca0..230c05e53403 100644
--- a/drivers/firmware/raspberrypi.c
+++ b/drivers/firmware/raspberrypi.c
@@ -12,6 +12,8 @@
#include <linux/of_platform.h>
#include <linux/platform_device.h>
#include <linux/slab.h>
+#include <linux/pci.h>
+#include <linux/delay.h>
#include <soc/bcm2835/raspberrypi-firmware.h>

#define MBOX_MSG(chan, data28) (((data28) & ~0xf) | ((chan) & 0xf))
@@ -19,6 +21,8 @@
#define MBOX_DATA28(msg) ((msg) & ~0xf)
#define MBOX_CHAN_PROPERTY 8

+#define VL805_PCI_CONFIG_VERSION_OFFSET 0x50
+
static struct platform_device *rpi_hwmon;
static struct platform_device *rpi_clk;

@@ -286,6 +290,54 @@ struct rpi_firmware *rpi_firmware_get(struct device_node *firmware_node)
}
EXPORT_SYMBOL_GPL(rpi_firmware_get);

+/*
+ * The Raspberry Pi 4 gets its USB functionality from VL805, a PCIe chip that
+ * implements xHCI. After a PCI reset, VL805's firmware may either be loaded
+ * directly from an EEPROM or, if not present, by the SoC's co-processor,
+ * VideoCore. RPi4's VideoCore OS contains both the non public firmware load
+ * logic and the VL805 firmware blob. This function triggers the aforementioned
+ * process.
+ */
+int rpi_firmware_init_vl805(struct pci_dev *pdev)
+{
+ struct device_node *fw_np;
+ struct rpi_firmware *fw;
+ u32 dev_addr, version;
+ int ret = 0;
+
+ fw_np = of_find_compatible_node(NULL, NULL,
+ "raspberrypi,bcm2835-firmware");
+ if (!fw_np)
+ return 0;
+
+ fw = rpi_firmware_get(fw_np);
+ of_node_put(fw_np);
+ if (!fw)
+ return -ENODEV;
+
+ /* Make sure we don't trigger a firmware load unnecesarely */
+ pci_read_config_dword(pdev, VL805_PCI_CONFIG_VERSION_OFFSET, &version);
+ if (version)
+ goto exit;
+
+ dev_addr = pdev->bus->number << 20 | PCI_SLOT(pdev->devfn) << 15 |
+ PCI_FUNC(pdev->devfn) << 12;
+
+ ret = rpi_firmware_property(fw, RPI_FIRMWARE_NOTIFY_XHCI_RESET,
+ &dev_addr, sizeof(dev_addr));
+ /* Wait for vl805 to startup */
+ udelay(200);
+
+exit:
+ if (!version)
+ pci_read_config_dword(pdev, VL805_PCI_CONFIG_VERSION_OFFSET,
+ &version);
+ pci_info(pdev, "VL805 firmware version %08x\n", version);
+ return ret;
+
+}
+EXPORT_SYMBOL_GPL(rpi_firmware_init_vl805);
+
static const struct of_device_id rpi_firmware_of_match[] = {
{ .compatible = "raspberrypi,bcm2835-firmware", },
{},
diff --git a/include/soc/bcm2835/raspberrypi-firmware.h b/include/soc/bcm2835/raspberrypi-firmware.h
index cc9cdbc66403..3025aca3c358 100644
--- a/include/soc/bcm2835/raspberrypi-firmware.h
+++ b/include/soc/bcm2835/raspberrypi-firmware.h
@@ -10,6 +10,7 @@
#include <linux/of_device.h>

struct rpi_firmware;
+struct pci_dev;

enum rpi_firmware_property_status {
RPI_FIRMWARE_STATUS_REQUEST = 0,
@@ -141,6 +142,7 @@ int rpi_firmware_property(struct rpi_firmware *fw,
int rpi_firmware_property_list(struct rpi_firmware *fw,
void *data, size_t tag_size);
struct rpi_firmware *rpi_firmware_get(struct device_node *firmware_node);
+int rpi_firmware_init_vl805(struct pci_dev *pdev);
#else
static inline int rpi_firmware_property(struct rpi_firmware *fw, u32 tag,
void *data, size_t len)
@@ -158,6 +160,11 @@ static inline struct rpi_firmware *rpi_firmware_get(struct device_node *firmware
{
return NULL;
}
+
+static inline int rpi_firmware_init_vl805(struct pci_dev *pdev)
+{
+ return 0;
+}
#endif

#endif /* __SOC_RASPBERRY_FIRMWARE_H__ */